A population of White Bearded De Brazza’s monkeys were sighted recently in the Great Rift Valley in Kenya, far from their original homes, raising concerns over climate change.

The monkeys have never been seen in the Rift Valley before. The monkeys were spotted in a forest area that had dried out as the climate in Kenya became more arid.

Richard Leakey, the son of famed paleontologist Louis Leakey, said the monkey population was one of many pieces of evidence for the growing effects of climate change in Africa, saying: “That is telling us a lot about the climate change scenarios we are looking at now. It puts climate change as the most critical consideration as we plan for the future.”

Leakey lashed out at African leaders, who he accused of ignoring the problem, and urged them to address environmental issues. “Why do we think that we are somehow not going to have to deal with this issue,” he said.

Africa has been hit especially hard by climate change. Although African nations emit significantly less CO2 than western nations, they have disproportionately felt the results of global warming.